ABSTRACT
Background
Hydroxyurea (HU) therapy improves the clinical severity of patients with hemoglobinopathies. Few studies have documented some mechanisms of HU, but the exact mechanism of action is unknown. Phosphatidylserine on erythrocytes is responsible for apoptosis. In this study, we investigate the expression of phosphatidylserine on the erythrocytes surface of hemoglobinopathies before and after HU treatment.
Research Designs and Methods
Blood samples from 45 thalassemia intermedia and 40 SCA and 30 HbE-b-thalassemia patients were analyzed before and after 3 and 6 months of HU treatment. The profile of phosphatidylserine was determined by flow-cytometry using the Annexin V-RBC apoptosis kit.
Results
Hydroxyurea proved effective in improving clinical severity of hemoglobinopathies. After treatment with hydroxyurea, the percentage of phosphatidylserine-positive cells was significantly reduced in all 3 patient groups (p < 0.0001). Correlation analysis using different hematological parameters as independent variables and % phosphatidylserine as dependent variable showed a negative relationship with HbF, RBC, and hemoglobin in all 3 patient groups.
Conclusion
Hydroxyurea reduces the expression of phosphatidylserine on erythrocytes, contributing to the beneficial effects of this therapy. We suggest that the use of such a biological marker in conjunction with HbF levels may provide valuable insights into the biology and consequences of early RBC apoptosis.
Plain Language Summary
The study investigated the role of hydroxyurea in reducing the externalization of phosphatidylserine on the surface of the erythrocyte membrane of patients with hemoglobinopathies. In patients treated with hydroxyurea for 3 and 6 months, the percentage of phosphatidylserine exposure on the erythrocyte surface was reduced compared with baseline. The decreased percentage of phosphatidylserine correlated negatively with hematologic parameters such as red blood cell (RBC), hemoglobin, and fetal hemoglobin (HbF) in patients at baseline and after HU therapy. Treatment with hydroxyurea decreases the percentage of PS exposure on the surface of RBCs, contributing to the beneficial effects of this therapy. We, therefore, suggest that the use of such a biological marker on the erythrocyte cell surface in conjunction with HbF levels may provide valuable insights into the biology and consequences of early erythrocyte apoptosis.
Declaration of interest
The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.
Reviewer disclosures
Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.
Ethics approval and patient consent
The study was approved by National Institute of Immunohaematology-Institutional Ethics Committee (letter number: NIIH/IEC/01–2017/) and all methods were performed in accordance with relevant guidelines and regulation. Written informed consent has been taken from patients recruited from study.
Acknowledgments
We are thankful to all patients and healthy individuals for their voluntary participation in the study. We are grateful to Indian Council of Medical Research (ICMR), Government of India, for providing us the research facilities.
Data availability statement
The datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request.
Supplementary material
Supplemental data for this article can be accessed online at https://doi.org/10.1080/17474086.2023.2231152.